<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>定义标题对齐方式</title>
</head>
<body>
<h1>这是一级标题</h1>
<h2 align="left">这是二级标题</h2>
<h3 align="center">这是三级标题</h3>
<h4 align="right">这是四级标题</h4>
</body>
</html>
